It has to do with the cocoa plant, and the cocoa. First the cocoa plant. The
cocoa plant takes two years to mature. This means that you can plant it one year
in a good area, and then do to things like El Nino or changes in the local
humidity and weather you now have a cocoa plant growing in a very poor area. The
obvious result is that during years of rapid temperature shifts you will have a
greater crop loss. Second the cocoa. The cocoa has oil in it, this means that
the cocoa will eventually rot. To put this in perspective you can store wheat
for twenty years, whereas you can not store cocoa for nearly that long. The
obvious result is that your cocoa supply is more sensitive to a poor crop year
than is wheat.

Now about the news. Lets deal with a little reality, there is no way to predict
the effect of the weather on the cocoa crop. It may result in a good year, or a
terrible year this year, and have quite the opposite affect two years from now.
So why do they report that there will be a shortage in cocoa. MONEY. Look at it
this way, you are looking to make some money, so you commission a dooms day
report from some speculators that know about as much as the next person about
the likelihood of a good crop five years from now, but you call them
consultants. You publish your report. Now it is on the news and people see that
cocoa is going to be in short supply so they go and by cocoa shares driving up
the price of the market. Over the next few years you sell your cocoa shares at a
high profit, easily covering the cost of the report from your favorite
consultant. You may even commission another report to say things look all rosy
now and drive the prices down and buy again.

The bottom line is, how are you going to predict the weather five years from now
when the weather man, who does weather predicitions professionally, can't
accurately predict the weather a week from now.